In: Physics
A car accelerates uniformly from rest and reaches a speed of 23.0 m/s in 8.96 s. Assume the diameter of a tire is 57.9 cm.
(a) Find the number of revolutions the tire makes during this
motion, assuming that no slipping occurs.
(b) What is the final angular speed of a tire in revolutions per
second?
rev/s
Initial speed of the car = V1 = 0 m/s
Final speed of the car = V2 = 23 m/s
Time period = T = 8.96 sec
Diameter of the tire = D = 57.9 cm = 0.579 m
Radius of the tire = R = D/2 = 0.2895 m
Initial angular speed of the tire = 1 = 0 rad/s
Final angular speed of the tire = 2
2 = V2/R
2 = 23/0.2895
2 = 79.447 rad/s
Angular acceleration of the tire =
2 = 1 + T
79.447 = 0 + (8.96)
= 8.867 rad/s2
Angle turned by the tires =
= 1T + T2/2
= (0)(8.96) + (8.867)(8.96)2/2
= 355.928 rad
Number of revolutions made by the tire = n
n = /2
n = 355.928/2
n =56.648 revolutions
2 = 79.447 rad/s
Converting to rev/s
2 = 79.447 x (1/2) rev/s
2 = 12.644 rev/s
a) Number of revolutions the tires make in this motion = 56.648
b) Final angular speed of the tire = 12.644 rev/s